The present invention generally relates to power tools and to blade dropping systems for such power tools.
Systems have been developed and are described in a plurality of patent applications that are assigned to SD2, LLC which include various mechanisms that have a detection system for detecting contact between a human and a blade The detection system triggers a brake mechanism that typically includes a pawl structure that is urged into the blade by a biasing mechanism that is retained by a fusible member and is melted by a high energy electrical current. Severing the fusible member releases the pawl to stop the blade or to retract it below the work surface of a table saw, for example. The systems have disadvantages; for example they are expensive and inconvenient to use since they require the replacement of expensive modules after they have been fired, which is time-consuming and difficult. An additional disadvantage is the variability of the system based on the blade design.